She and Kureno shared a brief romance, Kureno had experienced some of Akito's abuse. For example, whenever he left the main house without asking for her permission, she would slap and yell at him for doing so. Later, she stabbed him in the back with a knife, which hospitalized him.
Akito was Kureno's initial crush before Arisa. He used to spend a lot of time with Akito when they were kids and continued to do so as adults. The main reason why Kureno stayed with Akito was mainly pity, especially since his curse was broken before anyone else's. In his mid-teens, about ten years before the series begins, Kureno's curse was somehow broken, but because of Akito's distress he promised never to leave. Kureno and Akito have a sexual relationship, and when Shigure learned about it, some time before the start of the series, in retaliation he slept with Akito's mother, Ren. Akito keeps Kureno away from the rest of the family to hide that he is no longer cursed, and Kureno does most of Akito's work as the head of the family. Unlike the rest of his family, Kureno suffers the least amount of violence from Akito. Even when Akito stabbed him, he forgave her and she went to get help for him.
When he first visits a convenience store, where he meets Arisa. Despite their mutual attraction, he stays away from her because, he claims to Tohru, of his promise to Akito. However, when Akito locks Rin Soma away for trying to steal her father's box, it is Kureno who frees her. As the zodiac curse begins breaking down, Kureno eventually admits he is partially responsible for keeping Akito coddled and fearful by being too obedient, and Akito angrily stabs him in the back.
It gets a lot of attention from the fans, and as a result, a lot of fan arts and fan fictions. It's the most written ship for both characters on Archive of Our Own.